AUTHOR=Jiang Leiyu , Lin Yuanxiu , Wang Liangxin , Peng Yuting , Yang Min , Jiang Yuyan , Hou Guoyan , Liu Xiaoyang , Li Mengyao , Zhang Yunting , Zhang Yong , Chen Qing , Wang Yan , He Wen , Wang Xiaorong , Tang Haoru , Luo Ya 

TITLE=Genome-wide identification and expression profiling reveal the regulatory role of U-box E3 ubiquitin ligase genes in strawberry fruit ripening and abiotic stresses resistance

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1171056

DOI=10.3389/fpls.2023.1171056

ISSN=1664-462X

ABSTRACT=<p>The plant U-box (PUB) proteins are a type of E3 ubiquitin ligases well known for their functions in response to various stresses. They are also related to fruit development and ripening. However, PUB members possess such roles that remain unclear in strawberry. In this study, 155 <italic>PUB</italic> genes were identified in octoploid strawberry and classified into four groups. Their promoters possessed a variety of <italic>cis</italic>-acting elements, most of which are associated with abiotic stresses, followed by phytohormones response and development. Protein-protein interaction analysis suggested that FaU-box members could interact with each other as well as other proteins involved in hormone signaling and stress resistance. Transcriptome-based and RT-qPCR expression analysis revealed the potential involvement of <italic>FaU-box</italic> genes in resistance to stresses and fruit ripening. Of these, <italic>FaU-box98</italic> and <italic>FaU-box136</italic> were positively while <italic>FaU-box52</italic> was negatively related to strawberry ripening. <italic>FaU-box98</italic> comprehensively participated in resistance of ABA, cold, and salt, while <italic>FaU-box83</italic> and <italic>FaU-box136</italic> were broadly associated with drought and salt stresses. <italic>FaU-box18</italic> and <italic>FaU-box52</italic> were ABA-specific; <italic>FaU-box3</italic> was specific to salt stress. In addition, the functional analysis of a randomly selected <italic>FaU-box</italic> (<italic>FaU-box127</italic>) showed that the transient overexpression of <italic>FaU-box127</italic> promoted the ripening of strawberry fruit, along with significant changes in the expression levels of some ripening-related genes and the content of organic acid and soluble sugar. Overall, these findings provided comprehensive information about the <italic>FaU-box</italic> gene family and identified the potential FaU-box members participating in stress resistance and strawberry fruit ripening regulation.</p>